1. Field of the Invention
The present invention relates to a camera view finder display device designed so that the display portion is evenly illuminated and thus easily observed.
2. Description of the Prior Art
Generally, the display device in the view finder in the camera consists of a display portion, a light leading body for illuminating the display portion, a light source and a part of the view finder optics. In most cases, the light leading body consists of a triangular prism having a reflecting surface and two permeable surfaces.
The display portion is arranged in the neighborhood of a permeable surface of the triangular prism or is made as one illumination prism body with the triangular prism disposed in the optical path of the view finder optics. Further, the light source is arranged in the neighborhood of the optical path of the view finder optics to illuminate the display portion by means of the light leading body. The display portion is observed through a part of the view finder optics.
It is necessary that the light source for the display device in the view finder be placed in a small space in the camera body. Thus, it is desired that the light source be as small as possible. However, in order to illuminate the display portion evenly in the conventional view finder device as mentioned above, a large light source having a large light emitting portion becomes necessary. On the other hand, it is difficult to illuminate the display portion evenly by means of a small light source having a small light emitting portion.
Consequently, when a small light source is used, a dispersing plate is needed in front of the light emitting portion to disperse the light beam. The use of a dispersing plate is generally undesirable because the brightness of the display portion is decreased.
The display device in the view field is disclosed for example, in U.S. Pat. No. 3,416,422, Japanese Patent Publication No. Sho 54-28736, Japanese Utility Model Publication No. Sho 45-29582, Japanese Utility Model Publication No. Sho 48-38183, etc.